Choose the calculation you need, enter the values, and the calculator will show the answer with the formula used.
Enter the percentage you want to calculate.
Enter the number to apply it to.
Result
30
20% of 150 is 30.
Formula: 150 × 20 ÷ 100 = 30
Money examples should usually be rounded to 2 decimal places. For learning or checking a formula, use more decimal places.
How the percentage calculator works
This calculator covers the most common everyday percentage sums: percentage of a number, percentage increase, percentage decrease, percentage difference, and adding or subtracting a percentage.
Percentage of a number = number × percentage ÷ 100
Percentage change = (new value − old value) ÷ old value × 100
Percentage difference = |A − B| ÷ average of A and B × 100
The important part is choosing the right type of calculation. A percentage increase from 100 to 125 is 25%, but the percentage difference between 100 and 125 is 22.22% because it uses the average of both values. Related Calculatorz pages include How to calculate percentages, How to compare unit prices when shopping and proportion.
Percentage examples
20% of 150150 × 20 ÷ 100 = 30.
100 to 125The increase is 25 because 25 ÷ 100 × 100 = 25%.
Subtract 15% from £80£80 × 0.85 = £68.
Add 20% VAT to £100£100 × 1.20 = £120. Use the VAT calculator for full VAT breakdowns.
Common percentage mistakes
Percentage change is directional: from 100 to 125 is a 25% increase, but from 125 to 100 is a 20% decrease.
Percentage difference is different: it compares two numbers using their average.
Percentage points are not the same as percent: moving from 5% to 7% is a 2 percentage point rise, not a 2% rise.
Removing VAT is different from subtracting 20%: for 20% VAT, divide a VAT-inclusive price by 1.20.
Related everyday maths calculators
Use these calculators for common shopping, bill and invoice sums.